Responses to novelty differ among individuals and may be influenced by age, sex, and/or the presence of offspring. In this study, 20 captive Atlantic bottlenose dolphins (Tursiops truncatus) were exposed to a large novel object, consisting of PVC pipes and either a matte or reflective surface. The variation and changes in responses to these stimuli were recorded during 10 exposure trials. Adult females were most likely to interact with the object, and females with dependent calves tended to involve their calves in these interactions. Both adults and calves displayed significantly more interactions and more aggressive behaviors when exposed to the reflective surface, demonstrating that the characteristics of the apparatus influenced the response. Although the number of interactions did not change across repeated exposures, there were significantly more aggressive interactions during later exposures. There was no evidence of habituation over time for any of the subjects. These results suggest that marine mammal responses to novel stimuli are affected by the demographics of the population as well as the characteristics of the stimulus, which may contribute to habitation, sensitization, and/or tolerance.